Mac OS X Mavericks Is All About Energy-Efficiency and Extending the Life of Your Hardware

©. Apple

A pretty green update

Apple announced new gadgets on Tuesday, but what's most interesting from a treehugging perspective is the new software. More specifically, their new operating system, Mac OS X Mavericks. The first notable things are that it's free to download, and that it can be installed on any computer that could run Mountain Lion, the previous version of OS X (so iMacs going as far back as mid-2007 can upgrade -- that's an eternity ago in computing time).

This means that Apple wants it on as many of its computers as possible. That's good, because most of the work that has been done under the hood is focused on making applications more responsible, conserving resources, using less energy, and getting more out of the hardware that you already have.

Mac OS X Mavericks energy panel

Michael Graham Richard/Screen capture

How does Mavericks do what it does?

So last night, after checking on Twitter that people weren't having problems with upgrading to Mavericks, I took the plunge and installed it on my Mac. The download was slow, no doubt because tens of millions of people were trying to download the 5+ gig install file at the same time. But hey, at that price you can't complain!

I used that time to read John Siracusa's short-novel about OS X Mavericks. For a decade now, Siracusa has been writing the canonical review of every new version of OS X. Anything you want to know about it, down to what minute pixel changes took place, you can find in there. He went quite in depth into the energy-saving features. It might be too much unless you are also a computer geek, so here's the executive summary of what Mavericks does:

Mac OS X Mavericks

Apple/Screen capture

Keeping your CPU/GPU idle

One of the new tricks used by Mavericks is to keep your CPU and GPU in low-power states as much as possible. Not only are these the parts in your laptop or desktop that use the most power, but they are also the parts that show the most variance in power use. An idle CPU might use a fraction of 1 watt, while under load it might use more than 25 watts. The thing is, switching between a powered-down state and a load state isn't instantaneous, and if a variety of programs and OS processes keep asking the CPU to do a bit of works every few fractions of seconds, the CPU is spending less time in low-power mode than it could in theory.

To deal with that, Mavericks plays cowboy with all these programs and processes and wrangles them into more tightly packed-together herds so that the CPU can do a batch of them and then power down for a longer period of time. It's not a perfect metaphor (if you want the details, check out Siracusa's review), but the general idea is that by keeping requests to the CPU more tightly grouped together, Mavericks allows it to spend more time in low power mode, saving energy.

Mac OS X Mavericks

© Apple

Feel like taking a nap?

Another trick used by Mavericks to keep the CPU and GPU in low-power mode is to more aggressively restrict how much resources programs that aren't doing anything useful for the user can consume. Apple calls the feature "App Nap", and what it does is keep track of what you can and can't see, and it transparently (to you) stops putting lots of resources into programs that you can't see. So if you have a browser window and you hide it behind another window, App Nap will notice that and stop running the animations on the webpage in the browser. That saves energy.

Squeezing more into your RAM

Your computer puts the programs that are running into its memory (RAM). Nowadays, most computers typically have a few gigs of it (compared to hundreds of gigs of hard drive or SSD space). As long as you have enough RAM to fit all the programs you want, things are fine. But as soon as you run out of RAM, the computer needs to start writing things to the hard-drive and things slow down to a crawl because spinning hard drives are hundreds of thousands of time slower than RAM, and even fast SSDs are thousands of times slower. Mavericks has a new ace up its sleeve to get more out of your RAM: Apple calls it "Compressed Memory", and it works by transparently compressing portions of what's in RAM but isn't currently used using very fast algorithms that work a bit like when you turn a file into a .Zip or a .Rar, or a .JPG vs. a .BMP.

Bottom line is: Compressing things in memory tends to free up about 50% of the space. How much you gain depends on what you're doing, but in theory, you could fit about 6 gigs of stuff into 4 gigs of RAM.

Should you upgrade to OS X Mavericks?

All this should help extend the useful life of many computers, which is great to reduce e-waste, especially since Macs already tend to be less "disposable" and have longer lives than most PCs, and reduce the energy used, reducing CO2 emissions (not by a huge amount per computer, but multiply that by tens of millions of computers and it adds up).

In a test with a web-browsing script, John Siracusa found that upgrading a 2013 Macbook Air to Mavericks increased the already amazing battery life by about 3.5 hours! Even an old 2007 laptop (with a somewhat worn battery, I imagine) gained a significant amount of battery life.

Mavericks battery life

J. Siracusa/Screen capture

So based on that and my experience, I would definitely recommend upgrading to Mavericks. There are always some risks to upgrading an OS, so make sure you have a backup of all your data. But it's almost like getting a new, more responsive, more energy-efficient computer. And I didn't even get into the new features. What's not to like?

Please note: Right after installing Mavericks, the system needs to do a few things that can slow down your computer a bit (like Spotlight re-indexing the hard-drive, Mail re-indexing your emails, etc). This is only temporary. Don't judge the OS's performance until that's over.

Via Apple

See also: Apple now uses renewable energy for 75% of its needs